Physical Capital and ProductivityOther things equal, a greater quantity of physical capital per worker leads to higher real GDP per worker but is subject to diminishing returns: each successive addition to physical capital per worker produces a smaller increase in productivity. Starting at point A, with $20,000 in physical capital per worker, a $30,000 increase in physical capital per worker leads to an increase of $20,000 in real GDP per worker. At point B, with $50,000 in physical capital per worker, a $30,000 increase in physical capital per worker leads to an increase of only $10,000 in real GDP per worker.